Belts made of rubber find many uses in transferring power from a drive pulley to a driven pulley. Different types of belts include toothed belts, V-belts, V-ribbed belts, cogged belts and the like. Toothed belts have longitudinally spaced teeth that account for high efficiency power transfer because they mate with longitudinal grooves in the pulleys to eliminate slippage.
The belts often include a belt body having at least one surface covered with a facing fabric to form a surface that contacts the pulleys. For a toothed belt, the covered surface is a surface on the teeth.
The facing fabric typically includes a fabric of crimped yarn of 6-nylon or 6,6-nylon as the weft in the longitudinal direction of the belt and non-crimped yarn of 6-nylon or 6,6-nylon as the warp in the lateral direction of the belt. The facing fabric is coated with a resorcinol-formalin-latex (RFL) rubber solution. The RFL solution ensures a firm adhesion of the facing fabric to the belt surface.
Rubber at the contact surface of the belt body is removed in powder form due to abrasion caused by the pulleys. The rubber powder tends to adhere firmly to the pulleys to partially fill in the pulley grooves and induce slippage, which adversely affects performance. This problem is particularly troublesome in a driving section of a printer which uses a toothed belt and can result in poor printing performance.
Examined Japanese Utility Model Publication No. 33800/1993 discloses an example of a toothed belt having a facing fabric that is treated only by the RFL solution and not covered with rubber at least on the surface contacting the pulleys. This belt experiences enlarged openings in the facing fabric caused by abrasion. The rubber surface of the teeth is sometimes exposed through these enlarged openings. Some of the exposed rubber becomes a rubber powder due to abrasion and attaches to the pulley grooves to degrade performance, for example, the printing performance in a printer.
A power transmission belt having a facing fabric that does not deteriorate in use is highly desirable.